Electromagnetic clamping method

ABSTRACT

An apparatus may comprise a permanent magnet unit, an end effector, and an electromagnetic clamping device. The end effector may be capable of performing workpiece operations. The electromagnetic clamping device may have an activated state and a deactivated state.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of the filing date of correspondingU.S. Provisional Patent Application No. 61/098,370, entitled“Electromagnetic Clamping Device”, filed Sep. 19, 2008, which isincorporated herein by reference.

BACKGROUND INFORMATION

1. Field

The present disclosure relates generally to manufacturing and inparticular to a method and apparatus for processing a workpiece. Stillmore particularly, the present disclosure relates to a method andapparatus for clamping a workpiece to perform various operations on theworkpiece.

2. Background

Installation of rivets and/or other types of fasteners may be performedin large airframe structures. These airframe structures include, forexample, without limitation, wing and fuselage skins to supportingstructures, and other suitable structures. These types of installationsmay be performed using manual and/or computer-controlled machines.Clamping devices may be installed by drilling holes through a workpieceand installing temporary fasteners into the holes to clamp togetherparts that are to be joined. Next, a hole may be drilled through theworkpiece with a drill. A rivet or other type of fastener may beinstalled into the hole.

This type of process may be time consuming and expensive, especiallywhen performed manually in locations where an automated machine cannotaccess a workpiece. For example, without limitation, in fuselage barrelsand/or wing boxes, it may not be possible to install rivets withexisting automated machines, because a machine is unable tosimultaneously access both sides of these types of airframe structures.Most automated machines employ some version of a c-frame device, inwhich the workpiece to be operated on may be disposed between twoopposing jaws of the c-frame. The c-frame jaws may support tools suchas, for example, without limitation, drills and/or riveters.

Electromagnetic clamping techniques may also be used to performoperations such as, for example, without limitation, clamping, drilling,and/or fastener insertion. These types of techniques may useelectromagnets on one side of a workpiece and a magnetic material, suchas steel plates, on an opposite side of the workpiece for a clampingprocess. These steel plates may be relatively heavy when manipulated bya human operator. For example, without limitation, a steel plate mayweigh up to around 30 pounds.

A human operator may hold the steel plate in place on one side of aworkpiece, while the electromagnet may be positioned on the other sideof the workpiece. The electromagnet may be activated to clamp theworkpiece between the electromagnet and the steel plate. An operationmay then be performed on the workpiece. Thereafter, the electromagnetmay be turned off and the human operator may move the steel plate toanother location on the workpiece.

The electromagnet may then be engaged to clamp the workpiece with thesteel plate at that new location. Another operation may then beperformed. This process may be repeated hundreds of times for aworkpiece. Using steel plates may cause fatigue problems for personnelinstalling and/or removing these plates for clamping operation,especially in confined spaces such as a wing box.

Thus, the different currently available clamping mechanisms forprocessing workpieces with limited access space may be difficult toimplement. Accordingly, there is a need for a method and apparatus forminimizing the issues described above.

SUMMARY

In one advantageous embodiment, an apparatus may comprise a permanentmagnet unit, an end effector, and an electromagnetic clamping device.The end effector may be capable of performing workpiece operations. Theelectromagnetic clamping device may have an activated state and adeactivated state.

In another advantageous embodiment, an electromagnetic clamping systemmay be present for clamping a workpiece having a plurality ofcomponents, wherein the electromagnetic clamping system may comprise apermanent magnet unit. The permanent magnet unit may comprise a housing,a number of permanent magnets, a number of low friction surfacescomprising a number of wheels, an end effector, an electromagneticclamping device, a first coil system, a second coil system, a third coilsystem, and a core. The end effector may be capable of performingworkpiece operations, wherein the end effector comprises at least one ofa drill and a riveter. The electromagnetic clamping device may have anactivated state and a deactivated state, wherein the electromagneticclamping device may comprise a first coil system that may be capable ofgenerating a first magnetic field causing a number of normal force onthe permanent magnet unit and the electromagnetic clamping device; asecond coil system that may be capable of generating a second magneticfield causing a side force on the permanent magnet unit; and a thirdcoil system that may be capable of generating a third magnetic fieldcausing a rotational force on the permanent magnet unit. The core may becapable of providing access to a surface of the workpiece to perform theoperations on the workpiece. The core may be capable of concentrating aforce from a number of magnetic fields on a surface of the corecontacting the surface of the workpiece. The electromagnetic clampingdevice may generate the number of magnetic fields in the activated stateat a strength causing the permanent magnet unit to clamp the workpieceto the electromagnetic clamping device. The electromagnetic clampingdevice may change the strength of the number of magnetic fields in thedeactivated state to a level causing the permanent magnet unit to becomemoveable along the surface of the workpiece. When the electromagneticclamping device is in the deactivated state, the permanent magnet unitmay be in a rolling mode in which the number of wheels may engage thesurface of the workpiece and the number of permanent magnets may moveaway from the surface of the workpiece. Also, when the electromagneticclamping device is in the deactivated state, the permanent magnet unitmay generate a magnetic field such that movement of the electromagneticclamping device may pull the permanent magnet unit. When theelectromagnetic clamping device is in the activated state, the permanentmagnetic unit may be in a fixed mode in which the number of wheels maybe disengaged from the surface of the workpiece and the number ofpermanent magnets moves to engage the surface of the workpiece.

In yet another advantageous embodiment, a method may be present forperforming an operation on a workpiece. A permanent magnet unit may bepositioned on a first surface of the workpiece. An electromagneticclamping device may be positioned on a second surface of the workpiece,wherein the first surface opposes the second surface. Theelectromagnetic clamping device may be placed in an activated state suchthat a magnetic field clamps the workpiece between the electromagneticclamping device and the permanent magnet unit. An operation may beperformed on the workpiece.

In still yet another advantageous embodiment, a method may be presentfor performing an operation on a workpiece having at least twocomponents with an electromagnetic clamping system. A permanent magnetunit may be positioned in the electromagnetic clamping system on a firstsurface of the workpiece. An electromagnetic clamping device may bepositioned in the electromagnetic clamping system on a second surface ofthe workpiece, wherein the first surface may oppose the second surface.The electromagnetic clamping device may be placed in an activated statesuch that a magnetic field may clamp the workpiece between theelectromagnetic clamping device and the permanent magnet unit. Theoperation may be performed on the workpiece, wherein the operation maybe selected from at least one of a drilling operation and a fasteningoperation. The electromagnetic clamping device may be placed in adeactivated state after performing the operation such that theelectromagnetic clamping device may change a strength of the number offorces allowing the permanent magnet unit to become moveable on thefirst surface. The permanent magnet unit may be moved with theelectromagnetic clamping device by at least one of moving theelectromagnetic clamping device, wherein the electromagnetic clampingdevice may pull the permanent magnet unit and generating anothermagnetic field with a side force moving the permanent magnetic unit onthe first surface.

In a further advantageous embodiment, a method may be present forassembling parts. A sealant may be placed between a plurality of partsin a stack up to form a workpiece. The workpiece may be clamped using apermanent magnet unit and an electromagnetic clamping device in anactivated state such that a number of forces caused by a magnetic fieldmay clamp the workpiece between the electromagnetic clamping device andthe permanent magnet unit. A number of holes may be drilled in the workpiece, and a number of fasteners may be installed in the number ofholes.

The features, functions, and advantages can be achieved independently invarious embodiments of the present disclosure or may be combined in yetother embodiments in which further details can be seen with reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the advantageousembodiments are set forth in the appended claims. The advantageousembodiments, however, as well as a preferred mode of use, furtherobjectives and advantages thereof, will best be understood by referenceto the following detailed description of an advantageous embodiment ofthe present disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a diagram illustrating an aircraft manufacturing and servicemethod in accordance with an advantageous embodiment;

FIG. 2 is a diagram of an aircraft in which an advantageous embodimentmay be implemented;

FIG. 3 is a diagram of an electromagnetic clamping system in accordancewith an advantageous embodiment;

FIG. 4 is a diagram illustrating the use of an electromagnetic clampingdevice and a permanent magnet unit to provide clamping force inaccordance with an advantageous embodiment;

FIG. 5 is a diagram illustrating a change in clamping force between anelectromagnetic clamping device and a permanent magnet unit inaccordance with an advantageous embodiment;

FIG. 6 is a diagram illustrating electromagnetic forces that may begenerated between an electromagnetic clamping device and a permanentmagnet unit in accordance with an advantageous embodiment;

FIG. 7 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 8 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 9 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 10 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 11 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 12 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 13 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 14 is a diagram of a top cross-sectional view of an electromagneticclamping system in accordance with an advantageous embodiment;

FIG. 15 is a diagram of a side cross-sectional view of anelectromagnetic clamping system in accordance with an advantageousembodiment;

FIG. 16 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 17 is a diagram illustrating a cross-sectional side view of anelectromagnetic clamping system in accordance with an advantageousembodiment;

FIG. 18 is a diagram of a cross-sectional top view of an electromagneticclamping system in accordance with an advantageous embodiment;

FIG. 19 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 20 is a diagram illustrating an electromagnetic clamping system inaccordance with an advantageous embodiment;

FIG. 21 is a flowchart of a process for performing an operation on aworkpiece in accordance with an advantageous embodiment; and

FIG. 22 is a flowchart of an assembly process in accordance with anadvantageous embodiment.

DETAILED DESCRIPTION

Referring more particularly to the drawings, embodiments of thedisclosure may be described in the context of the aircraft manufacturingand service method 100 as shown in FIG. 1 and aircraft 200 as shown inFIG. 2. Turning first to FIG. 1, a diagram illustrating an aircraftmanufacturing and service method is depicted in accordance with anadvantageous embodiment. During pre-production, exemplary aircraftmanufacturing and service method 100 may include specification anddesign 102 of aircraft 200 in FIG. 2 and material procurement 104.

During production, component and subassembly manufacturing 106 andsystem integration 108 of aircraft 200 in FIG. 2 takes place.Thereafter, aircraft 200 in FIG. 2 may go through certification anddelivery 110 in order to be placed in service 112. While in service by acustomer, aircraft 200 in FIG. 2 may be scheduled for routinemaintenance and service 114, which may include modification,reconfiguration, refurbishment, and other maintenance or service.

Each of the processes of aircraft manufacturing and service method 100may be performed or carried out by a system integrator, a third party,and/or an operator. In these examples, the operator may be a customer.For the purposes of this description, a system integrator may include,without limitation, any number of aircraft manufacturers andmajor-system subcontractors; a third party may include, withoutlimitation, any number of venders, subcontractors, and suppliers; and anoperator may be an airline, leasing company, military entity, serviceorganization, and so on.

With reference now to FIG. 2, a diagram of an aircraft is depicted inwhich an advantageous embodiment may be implemented. In this example,aircraft 200 may be produced by aircraft manufacturing and servicemethod 100 in FIG. 1 and may include airframe 202 with a plurality ofsystems 204 and interior 206. Examples of systems 204 include one ormore of propulsion system 208, electrical system 210, hydraulic system212, and environmental system 214. Any number of other systems may beincluded. Although an aerospace example is shown, different advantageousembodiments may be applied to other industries, such as the automotiveindustry.

Apparatus and methods embodied herein may be employed during any one ormore of the stages of aircraft manufacturing and service method 100 inFIG. 1. For example, without limitation, components or subassembliesproduced in component and subassembly manufacturing 106 in FIG. 1 may befabricated or manufactured in a manner similar to components orsubassemblies produced while aircraft 200 is in service 112 in FIG. 1.

Also, one or more apparatus embodiments, method embodiments, or acombination thereof may be utilized during production stages, such ascomponent and subassembly manufacturing 106 and system integration 108in FIG. 1, for example, without limitation, by substantially expeditingthe assembly of or reducing the cost of aircraft 200.

Similarly, one or more of apparatus embodiments, method embodiments, ora combination thereof may be utilized during maintenance and service 114in FIG. 1. For example, without limitation, an electromagnetic clampingsystem in accordance with an advantageous embodiment may be used toclamp and/or secure a workpiece during component and subassemblymanufacturing 106, system integration 108, and/or during maintenance inservice 114.

The different advantageous embodiments recognize that currently usedclamping systems may be expensive and impractical. Further, thedifferent advantageous embodiments recognize and take into account thatthe use of steel plates, in currently available electromagnetic clampingsystems, requires positioning during various operations on a workpiece.The different advantageous embodiments recognize and take into accountthat in many cases, the architecture and/or size of a workpiece mayprevent the use of automated machinery such as, for example, withoutlimitation, robotic devices to perform clamping, drilling, fastening,and/or other operations on a workpiece.

Thus, the different advantageous embodiments provide a method andapparatus for clamping a workpiece. In the different advantageousembodiments, an electromagnetic clamping system may include a permanentmagnet unit, an electromagnetic clamping device, and an end effector.The electromagnetic clamping device may have an activated state and adeactivated state. During the activated state, the electromagneticclamping device may generate a force to cause the permanent magnet unitto be pulled towards the magnetic clamping device to clamp theworkpiece.

Different operations may then be performed on the workpiece with thesedevices in place. Thereafter, the electromagnetic clamping device maymove the permanent magnet unit to the next location on the workpiece toperform another operation. The electromagnetic clamping device mayprovide a different and/or lower magnetic field to move the permanentmagnet unit. The electromagnetic clamping device may generate arepelling force between the electromagnetic clamping device and thepermanent magnet. This type of field may be generated to preventaccidental clamping of parts during movement of the electromagneticclamping device.

With reference now to FIG. 3, a diagram of an electromagnetic clampingsystem is depicted in accordance with an advantageous embodiment. Inthis example, electromagnetic clamping system 300 may includeelectromagnetic clamping device 302, permanent magnet unit 304, and endeffector 306.

Permanent magnet unit 304 and electromagnetic clamping device 302 mayprovide clamping forces to clamp workpiece 308. Workpiece 308 may be astructure on which an operation may be performed. Workpiece 308 mayinclude multiple components that may be clamped together by permanentmagnet unit 304 and electromagnetic clamping device 302. For example,without limitation, workpiece 308 may include wing panel 310, spar 312,and other suitable components.

End effector 306 may be a device that may be capable of performingoperations on workpiece 308. These operations may include, for example,without limitation, drilling operations, fastening operations, sealingoperations, and other suitable operations. In these examples, endeffector 306 may be any tool needed to perform operations on workpiece308. For example, without limitation, end effector 306 may be drill 314,riveter 316, sealing tool 318, and/or some other suitable device.

In operation, electromagnetic clamping device 302 may generate magneticfields 320, which interacts with magnetic fields 322 in permanent magnetunit 304 as shown by arrow 324. This interaction may cause permanentmagnet unit 304 to be pulled towards first surface 326 andelectromagnetic clamping device 302 to be pulled towards second surface328 of workpiece 308 with clamping forces 329. The level of force mayvary, depending on magnetic fields 320 as generated by electromagneticclamping device 302.

In this example, permanent magnet unit 304 may have housing 330, whichmay contain permanent magnets 332, low friction surfaces 334, andbiasing system 336. Housing 330 may be made from different materials.For example, without limitation, any non-ferrous material may be usedsuch as, aluminum, plastic composites, and/or other suitable materials.Biasing system 336 may place permanent magnet unit 304 in a number ofdifferent modes. For example, without limitation, biasing system 336 mayplace permanent magnet unit 304 in fixed mode 338, moving mode 340,detached mode 341, and/or any other suitable mode.

In the different advantageous embodiments, the different modes forbiasing system 336 may be controlled by electromagnetic clamping device302 through magnetic fields 320. For example, without limitation, whenmagnetic fields 320 are high 337, biasing system 336 may be in fixedmode 338. When magnetic fields 320 are low 339, biasing system 336 maybe in moving mode 340. Electromagnetic clamping device 302 may generatea lower amount of force and/or no force in a manner that allowspermanent magnet unit 304 to continue to be held by electromagneticclamping device 302 against workpiece 308, but with less force.

In this state, electromagnetic clamping device 302 may move permanentmagnet unit 304. In these examples, high 337 may be when clamping forces329 are sufficient to clamp permanent magnet unit 304 andelectromagnetic clamping device 302 to workpiece 308 in a manner inwhich various operations may be performed on workpiece 308. Low 339 maybe when clamping forces 329 may be present at a lower level than high337, such that electromagnetic clamping device 302 may move permanentmagnet unit 304 along first surface 326 of workpiece 308. When magneticfields 320 are repelling 343, biasing system 336 may be in detached mode341.

When in fixed mode 338, permanent magnets 332 and/or housing 330 mayengage first surface 326 to provide force 342 in the direction of arrow344. This force may be provided through the interaction of magneticfields 322 with magnetic fields 320. In this mode, low friction surfaces334 may or may not engage first surface 326.

When biasing system 336 is in moving mode 340, permanent magnet 332 maybe moved away from first surface 326 in the direction of arrow 346. Inthis mode, biasing system 336 may move low friction surfaces 334 in thedirection of arrow 344 to engage first surface 326. Low frictionsurfaces 334 have a coefficient of friction that may allow permanentmagnet unit 304 to be moved along first surface 326 of workpiece 308. Inmoving mode 340, permanent magnet unit 304 may be moved along firstsurface 326 by electromagnetic clamping device 302.

In this mode, magnetic fields 320 are low 339, which have a strengththat is sufficient to interact with magnetic fields 322 to causepermanent magnet unit 304 to move, while biasing system 336 is in movingmode 340. This movement may be caused by movement of electromagneticclamping device 302 and/or through magnetic fields 320. In detached mode341, permanent magnet unit 304 may be detached from first surface 326.

In these examples, low friction surfaces 334 may take the form of wheels348. Wheels 348 may be, for example, without limitation, caster wheels.Of course, in other advantageous embodiments, other types of lowfriction surfaces may be used. Low friction surfaces that may be usedinclude, for example, without limitation, materials made offluoropolymers, and/or other suitable low friction materials. Onespecific example may be Teflon® pads. Teflon is a registered trademarkof the DuPont Company.

Biasing system 336 may move permanent magnet 332 and/or low frictionsurfaces 334 as different modes are entered using various mechanisms.For example, without limitation, spring 350 may bias permanent magnet332 in the direction of arrow 346, and lever 352 may bias low frictionsurfaces 334 in the different directions as shown by arrows 346 and 344.

In the different advantageous embodiments, electromagnetic clampingdevice 302 may include housing 354, which may contain coils 356 and core358. Housing 354 may be made of various materials. For example, withoutlimitation, housing 354 may be comprised of magnetic material 355. Amagnetic material in these examples is a material that may be magnetizedwhen magnetic fields 320 are generated. Magnetic material 355 may notinclude permanent magnet 360 in these examples. In some advantageousembodiments, housing 354 may be made from a combination of magneticmaterial 355 and permanent magnet 360. Coils 356 may include, forexample, without limitation, normal force coil 361, side force coil 362,and rotational force coil 364.

Normal force coil 361 may generate a number of magnetic fields withinmagnetic fields 320 to generate a substantially normal force to secondsurface 328 along the direction of arrow 366. A number of items, as usedherein, refers to one or more items. For example, without limitation, anumber of magnetic fields is one or more magnetic fields. Side forcecoil 362 may generate a number of magnetic fields within magnetic fields320 to generate side forces in the direction as indicated by arrow 368.Rotational force coil 364 may generate a number of magnetic fieldswithin magnetic fields 320 to create rotational forces as indicated byarrow 370.

Normal force coil 361 may generate a magnetic field in magnetic fields320 used to create clamping forces 329 to clamp permanent magnetic unit304 and electromagnetic clamping device 302 to workpiece 308. Side forcecoil 362 and/or rotational force coil 364 may generate a number ofmagnetic fields within magnetic fields 320 to pull or move permanentmagnet unit 304 along first surface 326 in the direction of arrow 368and/or arrow 370.

Movement of permanent magnet unit 304 may be performed by at least oneof generating forces with magnetic fields 320 and moving electromagneticclamping device 302. As used herein, the phrase “at least one of”, whenused with a list of items, means that different combinations of one ormore of the items may be used and only one of each item in the list maybe needed. For example, without limitation, “at least one of item A,item B, and item C” may include, for example, without limitation, itemA, or item A and item B. This example also may include item A, item B,and item C, or item B and item C.

The movement of permanent magnet unit 304 may not require movement ofelectromagnetic clamping device 302. Permanent magnet unit 304 may alsobe moved by moving electromagnetic clamping device 302 along thedirection of arrow 368 to pull permanent magnet unit 304 along thedirection of arrow 368.

Core 358 may provide a channel through housing 354 through which endeffector 306 may perform various operations on workpiece 308. In someexamples, permanent magnet 360 may be used in conjunction with coils 356to provide clamping forces 329.

Illustration of electromagnetic clamping system 300 in FIG. 3 is notmeant to imply physical or architectural limitations to the manner inwhich different advantageous embodiments may be implemented. Otherfunctions and/or features may be used in addition to or in place of theones illustrated in FIG. 3. For example, in some advantageousembodiments, a positioning feature may be present to identify theposition of permanent magnet unit 304 with respect to electromagneticclamping device 302.

In yet other advantageous embodiments, two permanent magnet units may beemployed rather than just permanent magnet unit 304. Further, in someadvantageous embodiments, one or more additional permanent magnets maybe used within or outside of housing 330 in addition to permanent magnet332. In yet another advantageous embodiment, electromagnetic clampingdevice 302 may have only a single coil instead of multiple coils. Forexample, without limitation, electromagnetic clamping device 302 mayonly contain normal force coil 361.

With reference now to FIG. 4, a diagram illustrating the use of anelectromagnetic clamping device and a permanent magnet unit to provideclamping force is depicted in accordance with an advantageousembodiment. Electromagnetic clamping system 400 is an example of oneimplementation for electromagnetic clamping system 300 in FIG. 3.

In this example, electromagnetic clamping device 401 in electromagneticclamping system 400 may generate magnetic field 402 that may interactwith magnetic field 404 as generated by permanent magnet unit 406, whichalso may be part of electromagnetic clamping system 400. In thisexample, electromagnetic clamping device 401 may generate a positivepolarity, such that magnetic field 404 is at high level 407 to generateclamping forces 408 and 410.

This interaction between magnetic field 402 and magnetic field 404 maycreate clamping forces 408 and 410, which pull electromagnetic clampingdevice 401 and permanent magnet unit 406 towards each other to clampworkpiece 412. The amount of clamping force created for clamping forces408 and 410 may vary depending on the strength of magnetic field 402 asgenerated by electromagnetic clamping device 401.

With reference now to FIG. 5, a diagram illustrating a change inclamping force between an electromagnetic clamping device and apermanent magnet unit is depicted in accordance with an advantageousembodiment. In this example, electromagnetic clamping device 401 mayhave changed the polarity in magnetic field 402. The interaction betweenmagnetic field 402 and magnetic field 404 may cause electromagneticclamping device 401 and permanent magnet unit 406 to repel from eachother away from workpiece 412. This type of interaction may be usefulwhen disengaging electromagnetic clamping device 401 and permanentmagnet unit 406 from workpiece 412.

With reference now to FIG. 6, a diagram illustrating electromagneticforces that may be generated between an electromagnetic clamping deviceand a permanent magnet unit is depicted in accordance with anadvantageous embodiment. In this diagram, graph 600 x-axis 602represents a gap, and y-axis 604 represents the clamping force. The gap,in these examples, may be a distance between electromagnetic clampingdevice 606 and permanent magnet unit 608. This gap may vary depending onthe size and/or thickness of the workpiece.

Line 610 illustrates clamping forces 612 and 614 generated byelectromagnetic clamping device 606 in an active and/or normal polaritybased on gap 615. Line 616 shows the clamping force generated betweenelectromagnetic clamping device 606 and permanent magnet unit 608 whenelectromagnetic clamping device 606 is deactivated. In line 616,electromagnetic clamping device 606 may cause clamping forces 612 and614 to have a lower level, allowing movement of permanent magnet unit608 by electromagnetic clamping device 606.

Line 618 may illustrate clamping forces 612 and 614 generated byelectromagnetic clamping device 606 and permanent magnet unit 608 whenelectromagnetic clamping device 606 has reversed polarity. Line 620 mayillustrate an amount of biasing or spring force that may be applied to apermanent magnet, in permanent magnet unit 608, to pull permanent magnetunit 608 away from electromagnetic clamping device 606.

With reference now to FIG. 7, a diagram illustrating a permanent magnetclamping system is depicted in accordance with an advantageousembodiment. Permanent magnet clamping system 700 may include permanentmagnet clamping device 702 and permanent magnet unit 704, which may beused to clamp workpiece 706 to perform various operations.

In this example, permanent magnet clamping device 702 may comprisepermanent magnet 708 and core 710. Core 710 may include channel 712,which may allow for drilling operations to be performed on surface 714of workpiece 706.

Permanent magnet unit 704 may include channels 716, 718, 720, 722, 724,726, and 728. One or more of these channels may be aligned with channel712 for use in drilling operations to be performed on workpiece 706. Inthis example, permanent magnet clamping device 702 may be in an activestate when in position 730. In position 732, permanent magnet unit 704may provide less clamping force with an increase of distance 734, Δh,from permanent magnet unit 704.

In this example, gap 736, t, may be present between electromagneticclamping device 702 in position 730 and permanent magnet unit 704.Clamping forces 738 and 740 exerted by permanent magnet clamping device702 and permanent magnet unit 704 may be calculated as follows:F_(c1)=f(t), f(t) is a function based on t. In these examples, gap 736,t, may be around zero inches to around one inch. The value of distance734, Ah, may indicate the level of clamping force. A value of zero fordistance 734, Δh, may indicate a clamping condition in which a clampingforce may be generated. A value greater than zero for distance 734, Δh,may indicate an unclamped condition in which a reduced or absentclamping force may be provided.

With reference now to FIG. 8, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. Electromagnetic clamping system 800 is an example of animplementation for electromagnetic clamping system 300 in FIG. 3. Inthis example, electromagnetic clamping system 800 may includeelectromagnetic clamping device 802 and permanent magnet unit 804.

In this example, electromagnetic clamping device 802 may include coils806, permanent magnet 808, permanent magnet 810, core 812, and housing814. Coils 806 may be integrated into housing 814 to generate magneticfields (not shown) along with magnetic fields (not shown) that may begenerated by permanent magnets 808 and 810. Housing 814 may be comprisedof a magnetic material such as, for example, without limitation, steel,which may be used to increase clamping forces 816 and 818.

Permanent magnet unit 804 may include channels 820, 822, 824, 826, 828,830, and 832. In this example, electromagnetic clamping device 802 andpermanent magnet unit 804 may provide forces to clamp workpiece 829.Electromagnetic clamping system 800 is an example of one implementationof electromagnetic clamping system 300 in FIG. 3.

In this example, when electromagnetic clamping device 802 is activated,electromagnetic clamping device 802 may pull permanent magnet unit 804in the direction of arrow 834 in a manner to clamp workpiece 829. Whenelectromagnetic clamping device 802 is deactivated, permanent magnets808 and 810 may still pull permanent magnet unit 804 towardselectromagnetic clamping device 802. Further, in the deactivated state,electromagnetic clamping device 802 may still generate clamping forces816 and 818 at a lower strength.

Clamping forces 816 and 818 may have less force that may allow formovement of electromagnetic clamping device 802 to also pull permanentmagnet unit 804 in the direction of arrow 831 when electromagneticclamping device 802 is moved in the direction of arrow 831. Whenelectromagnetic clamping device 802 is reversed in polarity, the changein force may be such that permanent magnet unit 804 may be removed ordetached.

With reference now to FIG. 9, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. Electromagnetic clamping system 900 is an illustration ofone implementation of electromagnetic clamping system 300 in FIG. 3.

In this example, electromagnetic clamping system 900 may includeelectromagnetic clamping device 902 and permanent magnet unit 904. Inthis example, electromagnetic clamping device 902 may include housing906, coil 908, and permanent magnet 910. In this example, coil 908 maybe attached to interior surface 912 of housing 906. Permanent magnet 910may be connected to coil 908. Housing 906, in these examples, may bemade of a magnetic material such as, for example, without limitation,steel and/or iron.

With reference now to FIG. 10, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. In this example, electromagnetic clamping system 1000 is anexample of one implementation for electromagnetic clamping system 300 inFIG. 3.

Electromagnetic clamping system 1000 may include electromagneticclamping device 1002 and permanent magnet unit 1004. Electromagneticclamping device 1002 may include housing 1006, coil 1008, and permanentmagnet 1010. In this example, permanent magnet 1010 may be attached tointerior surface 1012 of housing 1006. Coil 1008 is attached topermanent magnet 1010.

With reference now to FIG. 11, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. In this example, electromagnetic clamping system 1100 is anexample of yet another implementation for electromagnetic clampingsystem 300 in FIG. 3.

Electromagnetic clamping system 1100 may include electromagneticclamping device 1102 and permanent magnet unit 1104. Electromagneticclamping device 1102 may include housing 1106 and coil 1108. In thisexample, permanent magnet 1110 may be incorporated as part of housing1106. Section 1112 and section 1114 of housing 1106 may be made of amagnetic material such as, for example, without limitation, steel, iron,or some other suitable material. Coil 1108 may be attached to interiorsurface 1116 of permanent magnet 1110 in this example.

With reference now to FIG. 12, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. Electromagnetic clamping system 1200 is an example of animplementation of electromagnetic clamping system 300 in FIG. 3.

Electromagnetic clamping system 1200 may include electromagneticclamping device 1202 and permanent magnet unit 1204. In thisillustrative example, electromagnetic clamping device 1202 may includehousing 1206 and coil 1208. Coil 1208 is attached to inner surface 1210of housing 1206. Housing 1206 may include magnetic material section1212, permanent magnet section 1214, and permanent magnet section 1216.As can be seen in this example, both permanent magnet and non-permanentmagnet sections may be integrated into housing 1206.

With reference now to FIG. 13, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. In this example, a side cross-sectional view ofelectromagnetic clamping system 1300 is illustrated. Electromagneticclamping system 1300 is an example of one implementation ofelectromagnetic clamping system 300 in FIG. 3.

In this illustrative example, electromagnetic clamping system 1300 mayinclude electromagnetic clamping device 1302 and permanent magnet unit1304. These two components may clamp workpiece 1306 to allow fordifferent operations to be performed on workpiece 1306.

Electromagnetic clamping device 1302 includes housing 1308, core 1310having channel 1312, normal force coil 1314, side force coil 1316, andside force coil 1318. In this example, normal force coil 1314 maygenerate clamping forces 1319 and 1320, which may be approximatelynormal to surface 1322 of workpiece 1306. Side force coil 1316 and sideforce coil 1318 may generate a force that may be along the direction ofarrow 1324, which may be approximately parallel to surface 1322 ofworkpiece 1306.

Normal force coil 1314 may generate clamping forces 1319 and 1320 toclamp permanent magnet unit 1304 and electromagnetic clamping device1302 to workpiece 1306. Side force coil 1316 and side force coil 1318may generate magnetic forces that may cause permanent magnet unit 1304to move along surface 1326 of workpiece 1306 in the direction of arrow1324.

As a result, when normal force coil 1314 is deactivated, side forcecoils 1316 and 1318 may generate fields to move permanent magnet unit304 along the direction of arrow 1324. These fields also may be referredto as Lorenze forces. In the deactivated state of the normal force coil1314, permanent magnet 1304 may still generate forces 1319 and 1320 at alower level.

With reference now to FIG. 14, a diagram of a top cross-sectional viewof an electromagnetic clamping system is depicted in accordance with anadvantageous embodiment. This view is taken along lines 14-14 in FIG.13. In this view, side force coil 1400 and side force coil 1402 arevisible. Side force coil 1400 and side force coil 1402 may generate amagnetic field to move permanent magnet unit 1304 in the direction ofarrow 1404.

With reference now to FIG. 15, a diagram of a side cross-sectional viewof an electromagnetic clamping system is depicted in accordance with anadvantageous embodiment. In this example, electromagnetic clampingsystem 1500 is another example of an implementation for electromagneticclamping system 300 in FIG. 3.

Electromagnetic clamping system 1500 may include electromagneticclamping device 1502 and permanent magnet unit 1504. Electromagneticclamping device 1502 and permanent magnet unit 1504 may be used to clampworkpiece 1506 for performing various operations.

In this example, electromagnetic clamping device 1502 may have housing1508 with core 1510. Normal force coil 1512, side force coil 1514 may belocated in interior 1518 of housing 1508, and side force coil 1516 maybe located in interior 1519 of housing 1508. Handling device 1520 may beattached to surface 1522 of housing 1508. Handling device 1520 may be ahandle, a robotic arm, or some other suitable device for manipulatingand/or moving housing 1508.

Permanent magnet unit 1504 may include housing 1524, permanent magnet1526, permanent magnet 1528, and permanent magnet 1530. In thisconfiguration, permanent magnet 1526 and permanent magnet 1530 maygenerate magnetic fields 1532, and 1534 that may interact with magneticfields 1536 and 1538 generated by side force coil 1514 and side forcecoil 1516 to move permanent magnet unit 1504 along the direction ofarrow 1533.

Permanent magnet 1528 may generate magnetic fields 1540 that mayinteract with magnetic fields 1542 generated by normal force coil 1512to generate clamping forces 1544 and 1546 to clamp permanent magnet unit1504 and electromagnetic clamping device 1502 to workpiece 1506.

With reference now to FIG. 16, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. Electromagnetic clamping system 1600 is another exampleimplementation for electromagnetic clamping system 300 in FIG. 3.

Electromagnetic clamping system 1600 may include electromagneticclamping device 1602 and permanent magnet unit 1604. These twocomponents may be used to clamp workpiece 1606 for performing variousoperations.

Electromagnetic clamping device 1602 may include housing 1608, normalforce coil 1610, side force coil 1612, side force coil 1614, andhandling device 1616. In this example, normal force coil 1610 may belocated on interior surface 1618 of housing 1608. Side force coil 1612,side force coil 1614, and handling device 1616 may be attached toexterior surface 1620 of housing 1608.

Permanent magnet unit 1604 may include housing 1622, permanent magnet1624, permanent magnet 1626, permanent magnet 1628, and handling device1630. In this example, permanent magnet 1626 may be attached to interiorsurface 1632 of housing 1622. Permanent magnet 1624 and permanent magnet1628 may be attached to surfaces 1634 and 1636 of housing 1622. Handlingdevice 1630 may be attached to exterior surface 1638 of housing 1622.

Magnetic field 1640 and magnetic field 1642 may be generated betweenpermanent magnet 1624 and side force coil 1612 and to cause movement ofpermanent magnet unit 1604 along the direction of arrow 1656. Magneticfield 1644 and magnetic field 1646 may be generated between permanentmagnet 1628 and side force coil 1614 to move permanent magnet unit 1604along the direction of arrow 1656. Movement of permanent magnets 1624and 1628 may be driven by Lorentz forces. Magnetic field 1648 and 1650may be generated between permanent magnet 1626 and normal force coil1610 to generate clamping forces 1652 and 1654 to clamp permanent magnetunit 1604 and electromagnetic clamping device 1602 to workpiece 1606.

In these examples, handling device 1616 and handling device 1630 may beattachments to a robotic device that may move and/or handleelectromagnetic clamping device 1602 and permanent magnet unit 1604.

With reference now to FIG. 17, a diagram illustrating a cross-sectionalside view of an electromagnetic clamping system is depicted inaccordance with an advantageous embodiment. Electromagnetic clampingsystem 1700 is an illustration of one implementation for electromagneticclamping system 300 in FIG. 3.

Electromagnetic clamping system 1700 may include electromagneticclamping device 1702 and permanent magnet unit 1704. These twocomponents may provide a clamping force to workpiece 1706.Electromagnetic clamping device 1702 may include housing 1708, normalforce coil 1710, rotational force coil 1712, rotational force coil 1713,side force coil 1714, and core 1716. Core 1716 may include channel 1718.

In the illustrative example, normal force coil 1710 may generate amagnetic field capable of causing electromagnetic clamping device 1702and permanent magnet unit 1704 to move in the direction of arrows 1720and 1722 to provide a clamping force on workpiece 1706. Rotational forcecoils 1712 and 1713 may generate a magnetic field capable of movingpermanent magnet unit 1704 in the direction of arrow 1724 on surface1726 of workpiece 1706. Side force coil 1714 may generate a magneticfield capable of moving permanent magnet unit 1704 along surface 1726 inthe direction of arrow 1728.

Rotational force coils 1712 and 1713 generate a magnetic field that mayinteract with the magnetic field of permanent magnet unit 1704 to causethe movement of permanent magnet unit 1704 in the direction of arrow1724. Side force coil 1714 generates the magnetic field which interactswith the magnetic field generated by permanent magnet unit 1704 to movepermanent magnet unit 1704 in the direction of arrow 1728. Rotationalforce coils 1712 and 1713 may generate the magnetic field in a mannerthat interacts with the magnetic field generated by permanent magnetunit 1704 to move permanent magnet unit 1704 in the direction of arrow1724.

With reference now to FIG. 18, a diagram of a cross-sectional top viewof an electromagnetic clamping system is depicted in accordance with anadvantageous embodiment. In this example, side force coil 1800 also maybe seen. Rotational force coil 1712 may generate a force along thedirection of arrow 1802, while rotational force coil 1713 may generateforce in response to a reaction of magnetic forces generated byrotational force coil 1712, rotational force coil 1713, and permanentmagnet unit 1704 (not shown), along the direction of arrow 1804 togenerate rotational movement as illustrated by arrow 1806.

Side force coil 1714 may generate a force in response to an interactionbetween the magnetic force generated by side force coil 1714 andpermanent magnet unit 1704 to move permanent magnet unit 1704, in thedirection of arrow 1808, while side force coil 1800 may produce forcefrom the interaction of a magnetic field generated by side force coil1800 and permanent magnet unit 1704 to move permanent magnet unit 1704along the direction of arrow 1810.

With reference now to FIG. 19, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. Electromagnetic clamping system 1900 is an example of oneimplementation for electromagnetic clamping system 300 in FIG. 3.

In this example, electromagnetic clamping system 1900 may includeelectromagnetic clamping device 1902 and permanent magnet unit 1904.Permanent magnet unit 1904 may include housing 1906, permanent magnet1908, wheel 1910, wheel 1912, spring 1909, lever 1911, and lever 1913.As illustrated, permanent magnet unit 1904 may be in a moving mode. Inthis mode, wheel 1910 and wheel 1912 may contact surface 1914 ofworkpiece 1920. Permanent magnet 1908 may be biased away from surface1914 of workpiece 1920 by spring 1909.

Spring 1909 may be connected to interior surface 1918 of housing 1906and permanent magnet 1908. Spring 1909 biases permanent magnet 1908 inthe direction of arrow 1917. When permanent magnet 1908 is biased awayfrom surface 1914 of workpiece 1920, levers 1911 and 1913 may pivotabout pivot points 1922 and 1924 to bias wheel 1910 and wheel 1912 ontosurface 1914 of workpiece 1920.

This configuration of permanent magnet unit 1904 may allow permanentmagnet unit 1904 to be moved by electromagnetic clamping device 1902.Electromagnetic clamping device 1902 may generate magnetic forces in thedirection of arrows 1926, 1928, and 1930 to move permanent magnet unit1904 in similar directions on surface 1914 of workpiece 1920.

In this example, arrow 1926 points to the left of electromagneticclamping device 1902, arrow 1928 points to the right of electromagneticclamping device 1902, and arrow 1930 points outward from electromagneticclamping device 1902. Of course, electromagnetic clamping device 1902also may be physically moved to cause permanent magnet unit 1904 to movein these different directions.

With reference now to FIG. 20, a diagram illustrating an electromagneticclamping system is depicted in accordance with an advantageousembodiment. In this example, permanent magnet unit 1904 may be in afixed mode.

In this mode, electromagnetic clamping device 1902 may generate aclamping force as illustrated by arrow 2000 to pull permanent magnet1908 to surface 1914 of workpiece 1920 to clamp workpiece 1920 betweenpermanent magnet unit 1904 and electromagnetic clamping device 1902.

When permanent magnet 1908 is biased to contact surface 1914, wheels1910 and 1912 may no longer be biased toward surface 1914. In thismanner, permanent magnet unit 1904 may be placed into a fixed mode toperform various operations. In this example, wheels 1910 and 1912provide a low friction surface, while surfaces 2002 and 2004 on housing1906, and surface 2006 on permanent magnet 1908 provide a high frictionsurface. As a result, workpiece 1920 may be secured between permanentmagnet unit 1904 and electromagnetic clamping device 1902.

With reference now to FIG. 21, a flowchart of a process for performingan operation on a workpiece is depicted in accordance with anadvantageous embodiment. The process illustrated in FIG. 21 may beimplemented using an electromagnetic clamping system, such aselectromagnetic clamping system 300 in FIG. 3.

The process may begin by positioning permanent magnet unit 304 on firstsurface 326 of workpiece 308 (operation 2100). The process positionselectromagnetic clamping device 302 on second surface 328 of workpiece308 (operation 2102). Second surface 328 may oppose first surface 326 ofworkpiece 308. The process may place electromagnetic clamping device 302in an activated state, such that magnetic fields 320 and 322 clampworkpiece 308 between electromagnetic clamping device 302 and permanentmagnet unit 304 (operation 2104).

The process may then perform an operation on workpiece 308 using endeffector 306 (operation 2106). This operation may be, for example,without limitation, a drilling operation, a sealing operation, afastening operation, and/or some other suitable operation. Operation2106 may employ a number of different operations for assembling astructure and/or object from a number of parts. This operation mayinclude, for example, sealing, clamping, drilling, and installingfasteners to assemble the structure from two or more parts. With thedifferent advantageous embodiments, other operations that may haverequired separating the parts after drilling and performing deburring,clean up, and then adding sealant may be avoided.

The process may place the electromagnetic clamping device in adeactivated state after performing the operation, such that theelectromagnetic clamping device changes the strength of magnetic fields320 and 322 allowing permanent magnet unit 304 to become moveable onfirst surface 326 (operation 2108).

The process may then move permanent magnet unit 304 with electromagneticclamping device 302 to another location (operation 2110), with theprocess terminating thereafter. At this point, the process may berepeated to perform another operation on workpiece 308. The movement ofthe permanent magnetic unit 304 in operation 2110 may be performed bymoving electromagnetic clamping device 302 and/or generating magneticfields 320 and 322 with a force capable of moving permanent magnet unit304 along the surface of workpiece 308.

The different operations illustrated in FIG. 21 are provided forpurposes of illustrating one manner in which a clamping process may beperformed on workpiece 308 to perform an operation on workpiece 308. Inother advantageous embodiments, other operations in addition to or inplace of the ones illustrated may be performed. For example, withoutlimitation, instead of performing a single operation in operation 2106,multiple operations may be performed. For example, without limitation, ahole may be drilled in the workpiece and then a fastener may be placedinto the hole in the workpiece.

With reference now to FIG. 22, a flowchart of an assembly process isdepicted in accordance with an advantageous embodiment. The assemblyprocess illustrated in FIG. 22 may be implemented using anelectromagnetic clamping system, such as electromagnetic clamping system300 in FIG. 3.

The process may begin by placing sealant between parts in a stack up toform workpiece 308 (operation 2200). The process clamps workpiece 308using electromagnetic clamping system 300 (operation 2202). The processdrills a number of holes in workpiece 308 (operation 2204).

Next, a number of fasteners may be installed in the number of holes(operation 2206). The workpiece may then be unclamped (operation 2208).A determination may then be made as to whether additional drillingand/or fastening operations are to be performed (operation 2210). Ifadditional drilling and/or fastening operations are needed, clampingsystem 300 may be moved to another location on the workpiece, and theprocess returns to operation 2202. If additional drilling and/orfastening operations are not needed in operation 2210, the process mayterminate.

Operations 2204 and 2206 may be performed sequentially or concurrently.In other words, each time a hole is drilled, a fastener may beinstalled. In other advantageous embodiments, all the holes may bedrilled prior to installing fasteners.

Thus, the different advantageous embodiments provide a method andapparatus for performing operations on a workpiece. In the differentadvantageous embodiments, a permanent magnet unit, an end effector, andan electromagnetic clamping device may be used to perform the differentoperations.

With the different advantageous embodiments, the use of steel plates andthe fatigue that the steel plates may cause may be avoided. Further, thedifferent advantageous embodiments provide a capability to move apermanent magnet unit through magnetic forces generated by anelectromagnetic clamping device. In this manner, only a single operatormay be needed to perform different operations. For example, withoutlimitation, an operator may operate and move the electromagneticclamping device with the end effector on one side of the workpiecewithout requiring another operator to be present on the opposite side.This type of capability may be especially useful when the type ofworkpiece may limit access to both sides of the workpiece.

As a result, one or more of the different advantageous embodiments maybe employed in a manner to clamp parts that may eliminate gaps betweenparts. Further, the different advantageous embodiments may be used forperforming various assembly operations. These assembly operations mayinclude, for example, without limitation, squeezing sealant applied topart interfaces, enabling no burrs between parts of clamp up duringdrilling, and other suitable operations.

As described above, the different advantageous embodiments may employ anelectromagnetic clamping device to pull a permanent magnet on anopposite side of the part towards the electromagnetic clamping device.Further, in some advantageous embodiments, the electromagnetic clampingdevice may move the permanent magnet, which may have an end effectorattached, sideways. This movement may be performed by reversing theelectromagnetic polarity, generating a low repelling normal flow offorce, and towing the permanent magnet with reduced friction during sidemotion. Also, additional coils may be present within the electromagneticclamping device to employ Lorenze forces to move the permanent magnetsideways.

The description of the different advantageous embodiments has beenpresented for purposes of illustration and description, and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. For example, without limitation, the different advantageousembodiments have been described with respect to clamping workpieces inthe form of aircraft parts.

Other advantageous embodiments may be applied to clamping parts and/orcomponents for other structures other than aircraft. For example, otheradvantageous embodiments may be employed to clamp workpieces forautomobiles, spacecraft, submarines, molds, and other suitablestructures. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different advantageousembodiments may provide different advantages as compared to otheradvantageous embodiments.

The embodiment or embodiments selected are chosen and described in orderto best explain the principles of the embodiments, the practicalapplication, and to enable others of ordinary skill in the art tounderstand the disclosure for various embodiments with variousmodifications as are suited to the particular use contemplated.

1-22. (canceled)
 23. A method for assembling parts, the methodcomprising: placing a sealant between a plurality of parts in a stack upto form a workpiece; clamping the workpiece using a permanent magnetunit and an electromagnetic clamping device in an activated state suchthat a number of forces caused by a magnetic field clamps the workpiecebetween the electromagnetic clamping device and the permanent magnetunit; drilling a number of holes in the workpiece; and installing anumber of fasteners in the number of holes.
 24. The method of claim 23,wherein the permanent magnet unit further comprises: the first leverhaving a first end and a second end, the first lever connecting to thehousing at a first pivot point, and also connecting to the permanentmagnet unit at about the first end, the second end of the first leverconnecting to the first wheel; the second lever having a third end and afourth end, the second lever connecting to the housing at a second pivotpoint and also connecting to the permanent magnet at about the third endand further connecting to the permanent magnet unit opposite the firstlever, the fourth end of the second lever connecting to the secondwheel; and the end effector attaching to the housing between the firstwheel and the second wheel.
 25. The method of claim 24, the housinghaving one of a same material throughout and a combination of material,wherein the housing material comprises at least one of non-ferrousmaterials, aluminum, plastic composites, magnetic materials, iron, andsteel.
 26. The method of claim 24, wherein the first wheel and thesecond wheel are caster wheels.
 27. The method of claim 26, wherein thefirst wheel and the second wheel are low friction surfaces made of lowfriction materials.
 28. The method of claim 27, wherein the low frictionsurfaces comprise fluoropolymer materials.
 29. The method of claim 28,wherein the housing has one of a same material throughout and acombination of material, wherein the housing material comprises at leastone of non-ferrous materials, aluminum, plastic composites, magneticmaterials, iron, and steel.
 30. The method of claim 29, wherein thefirst wheel and the second wheel are caster wheels.
 31. The method ofclaim 30, wherein the first wheel and the second wheel are low frictionsurfaces made of low friction materials.
 32. The method of claim 31,wherein the low friction materials are fluoropolymers.
 33. The method ofclaim 23 wherein clamping the workpiece further comprises: positioningthe electromagnetic clamping device on a second surface of theworkpiece, wherein the first surface opposes the second surface, theelectromagnetic clamping device having an activated state and adeactivated state.
 34. The method of claim 33 further comprising:placing the electromagnetic clamping device in a deactivated state afterperforming the operation; pulling the permanent magnet unit, using thespring, away from the electromagnetic clamping device and towards thehousing; pivoting the first lever and the second lever, correspondinglyabout the first pivot point and the second pivot point as the permanentmagnet unit is pulled away from the electromagnetic clamping device;lowering the first wheel and the second wheel, using the first lever andthe second lever respectively, towards the workpiece; and moving thepermanent magnet unit with the electromagnetic clamping device on thefirst surface.
 35. The method of claim 34, wherein the moving stepcomprises: moving the electromagnetic clamping device, wherein theelectromagnetic clamping device pulls the permanent magnet unit.
 36. Themethod of claim 34, wherein the moving step comprises: generatinganother magnetic field to cause a side force to move the permanentmagnetic unit on the first surface.
 37. The method of claim 36, whereinthe workpiece comprises two components.
 38. The method of claim 23,wherein the workpiece comprises two components.